try:
    # 尝试打开文件
    with open('nonexistent_file.txt', 'r', encoding='utf-8') as file:
        content = file.read()
except FileNotFoundError as e:
    # 捕获文件未找到异常
    print(f"文件未找到: {e}")
except Exception as e:
    # 捕获其他异常
    print(f"发生未知错误: {e}")
else:
    # 如果没有异常发生，执行此代码块
    print("文件读取成功")
    print(content)
finally:
    # 无论是否发生异常，都会执行此代码块
    print("文件操作结束")